A variety of state-of-the-art medical procedures are conducted in connection with imaging. Common imaging modalities include x-ray, CT (computed tomography), MRI (magnetic resonance imaging), and ultrasound. Imaging may enable a clinician, such as a surgeon, to visualize features inside of a patient's body without requiring the clinician to make large incisions in the patient's body and, thus, “open the body up.” Thus, imaging may enable the clinician to conduct less invasive procedures on patients, including so-called “minimally invasive” procedures.
In one example of a minimally invasive procedure—image-guided radiation therapy (IGRT)—real-time imaging is used to precisely deliver radiation therapy to tumors. IGRT uses orthogonal x-rays to visualize one or more radio-opaque fiducial markings on the skin adjacent to the tumor or implanted within soft tissue adjacent to the tumor. These radio-opaque markings act as aids for real-time tracking of the radiotherapy beam during the treatment cycle. Radiation therapy can be delivered in a single dose (i.e., in one single procedure) or in up to five (5) doses. A robotic system delivers highly focused radiation from a single, highly collimated beam from hundreds of angles.
Minimally invasive procedures have also become an essential part of modern surgical techniques with enormous benefits to healthcare including: (a) increased safety to patients resulting from smaller incisions, with less trauma and far less blood loss; (b) decreased scarring, with typical incisions requiring one or two stitches or staples to close the surgical wound; (c) faster recovery, with patients often being discharged the same day and requiring one to two weeks of recovery compared to those with traditional surgeries typically requiring six to eight weeks; and (d) decreased length of hospital stay, with patients being discharged within a twenty-three (23) hour period or scheduled for outpatient surgery, resulting in a significant cost savings.
The success of many modern minimally invasive procedures requires that the treatment (e.g., surgery, beam placement, etc.) be targeted to a precise location within the patient's body. Stringent requirements have been placed on the accuracy of targeting of minimally invasive treatments to prevent the inadvertent performance of a procedure at the wrong site.
Imaging is used in conjunction with a variety of minimally invasive surgical procedures. For example, endovascular treatments, such as the treatment of peripheral arterial disease (PAD), involves image-guided endovascular intervention. PAD affects over 8 million Americans with significant associated morbidity and mortality, with about 2 million revascularizations, bypasses, arthrectomies, and angioplasty procedures being performed annually. Given the success of such procedures, physicians now advocate an “endovascular first” strategy.
As another example, imaging is used in connection with percutaneous biopsies, a rapidly growing common procedure in oncology. Minimally invasive spine surgery is performed to stabilize the vertebral bones and spinal joints and/or relieve pressures applied to the spinal nerves—often as a result of conditions such as a spinal instability, bone spurs, herniated discs, scoliosis or spinal tumors. As small, undetected movements of a patient can result in catastrophic injury to the patient, precise treatment is extremely important. In addition to the foregoing, the use of minimally invasive procedures continues to increase in a variety of specialties, including, but not limited to, neurovascular, gynecological, electrophysiological, orthopedic, and critical care procedures.
Surgical errors in which a surgeon performs the incorrect procedure, operates at the wrong site, or operates on the wrong patient are likely the third leading cause of death in the United States of America. It is believed that these types of surgical errors, which may occur in operating rooms and a variety of other settings (e.g., special procedures units, endoscopy units, interventional radiology suites, etc.) are currently responsible for about 400,000 deaths in the U.S. each year. Wrong site surgery is widely regarded as the most common of these types of surgical errors. In response, the Joint Commission published a Universal Protocol for Preventing Wrong Site, Wrong Procedure, and Wrong Person Surgery, which places emphasis on marking of the incision or insertion site, especially where there is more than one possible location for the procedure, or when performing the procedure would adversely affect patient outcomes and quality of life.
Marking the treatment site is vital to obtaining successful outcomes. Despite the rise in image guided procedures, traditional surgical site marking solutions that remain invisible under fluoroscopic imaging are still being employed. A variety of techniques have been used in an effort to ensure that minimally invasive treatments are properly targeted. Slight movements by the patient (e.g., those caused as the patient breathes, as his or her heart beats, etc.) during IGRT may be accounted for by having the patient wear a special vest that has light-emitting diodes (LEDs) that are detected and tracked by a ceiling-mounted camera array, displayed on a computer monitor, and used to adjust the delivery of radiation according to the patient's respiration or other movements. Thus, the system makes continuous adjustments to deliver the radiation beam to the tumor, allowing for a reduced dose of radiation in treatment margins. While the LEDs enable automated tracking of slight movements by the patient, they may not be visible, or useful as reference points, to a clinician as he or she relies on imaging to conduct a procedure at a particular location. Moreover, the LEDs of such a vest cannot be positioned at specific locations on a patient's body, and they cannot provide customized markings (e.g., fiducial marks, alphanumeric characters, symbols, etc.).
To date, the markers that are available to clinicians for clearly and distinctively marking the skin of patients (e.g., to identify patients, treatment sites, treatment procedures, etc.) are visible to the naked eye, but do not provide any indication of site location and or references to other anatomic landmarks when viewed under common imaging modalities. Moreover, the markings that may be made on a patient with currently available markers do not remain visible after a patient has been covered with drapes or other similar items; thus, concerns of wrong site, wrong patient, and wrong-procedure are not adequately addressed.
In an effort to address these issues, some radio-opaque markings have been developed. These include adhesive radio-opaque markings (i.e., stickers, decals, etc.) with pre-defined elements, such as lines, alphanumeric characters, or arrows or other symbols, that are visible and that may be seen under one or more common types of imaging. While the pre-defined elements may be placed at desired locations on a patient's skin, they do not afford the flexibility of a free-form mark that is versatile and convenient for the clinician in marking.
While the use of radio-opaque marking materials has been suggested, those marking materials suffer from many shortcomings. These shortcomings are largely due to the composition of the radio-opaque marking materials that have been proposed, which are typically thick, are difficult to apply (e.g., by requiring excessive force, because they cannot be applied in a smooth, continuous manner, etc.), and do not remain on the surfaces to which they are applied (e.g., a patient's skin, etc.). The results are easily removable marks of poor definition, limiting the ability of such a radio-opaque material to provide the types of instructions that are useful in properly identifying a patient, a treatment site, and a treatment procedure.